[Pitch] Package Manager: Statically link Swift runtime libraries by default on supported platforms

[tomerd]

@John_McCall

Hmm. I assume it must've been a philosophical decision to not have that. I find that pretty surprising;

I do not know why such was not added originally. cc @ddunbar

@John_McCall

it certainly seems to assume that there's one standard way that executables should be built on a platform, which puts us in the unfortunate position of having to pick that globally.

This focus of the proposal is about what would be considered a sensible default. Even if we decide to add some sort of build settings section to the manifest to capture the user's preference (which seems like a good but additive suggestion), SwiftPM would still need to have a default behavior when such are not specified. Right now, that default behavior across all platforms is dynamic linking [of the runtime libraries], but one could argue the default should be different across platforms, reflecting how the Swift runtime is distributed on those platforms.

@John_McCall

Dynamic linking is a more reasonable default for a lot of use cases even on Linux;

Given that no Linux distribution ships the Swift runtime libraries, nor is there a stable ABI for Swift on Linux, the proposal argues that the sensible default on Linux should be static linking [of the runtime libraries]. If and when a Linux distribution ships with a runtime, the toolchain on that distribution could change this default to reflect that, or we could decide to further refine the behavior.